class PoolError extends Error{
  constructor(code) {
    super();
    this.code = code;
  };
}

PoolError.PUSH_TIMEWAIT_INVALID = 1;    //push的timewait参数非法
PoolError.INSTANCE_TYPE_ERROR = 2;    //实例类型不匹配
PoolError.POP_TIMEWAIT_INVALID = 3;   //pop的timewait参数非法
PoolError.POP_TIMEOUT = 4;    //pop超时

module.exports = PoolError;